1. Field of the Invention
This invention relates to an electronic private branch exchange system with the function of recording conversation over an extension telephone, which is installed in an office, a business building, a school, or the like.
2. Description of the Related Art
Recently, various service functions have been available with an electronic private branch exchange system. One of them is a message recording function such as voice mail. The recording function is realized by, for example, incorporating a recorder in an electronic private branch exchange or adding the former to the latter to record conversation over an extension telephone on the recorder. One typical use of the massage recording function is, for example, a telephone answering machine which records the message from the caller when the called extension telephone has not answered.
For another use of the message recording function, a method has recently been considered where conversation over the called extension is recorded on a recorder when the called extension telephone has answered, and the talk recorded on the recorder is reproduced as the need arises after the call has finished. With this method, the contents of the talk can be analyzed or confirmed. This use makes it possible to reconfirm the calling party's name, company name, the contents of the important message, etc. after the call has finished, which is very convenient.
To realize the use, the user of a conventional extension telephone operates particular keys including function keys after having made a terminating call response, in order to instruct a private branch exchange to record. Receiving the recording instruction, the private branch exchange actuates a recorder to record conversation over the extension telephone. Because the user operates to specify a recording operation as the occasion demands while talking, he may fail to record the important message from the other party while operating to specify recording or may be unable to record the other party's name and company name given immediately after the terminating call response.
To solve the problem, a system has been proposed which provides a "Message Recording" class for subscribers to an ISDN or the like, and causes a three-party talk connecting function and a message recorder to record conversation automatically (Jpn. Pat. Appln. KOKAI Publication No. 62-266956). Since the system previously allocates "Message Recording" class to the subscribers who need message recording, all subscribers (or the users of extension telephones in the electronic private branch exchange) cannot use the message recording function equally. Additionally, the procedure for changing subscribers (or users of extension telephones) who need message recording is troublesome. Furthermore, because a conventional system records all the calls the subscribers made, none of the subscribers (or the users of the extension telephones) can record talks as the need arises.